Modular structure for maintaining a body part

ABSTRACT

The invention concerns a structure for maintaining a body part, the structure consisting of assembled frame members, at least one of the frame members being a tubular beam ( 1 ) provided on the outside with at least a groove ( 7 ) extending longitudinally. The invention also concerns a template for drilling said beam.

The present invention relates to a structure for holding bodywork parts.

BACKGROUND OF THE INVENTION

In car bodywork assembly lines, subassemblies (such as the subframe, thesides of the body, the rear skirt, . . . ) are positioned relative toone another and relative to welding robots. By their very nature,bodywork parts are deformable on being subjected to stresses, so thetooling used for making bodywork of determined and reproducible shapeperforms two functions: firstly it constitutes framework for eachdeformable subassembly for the purpose of stiffening it to enable it tobe handled by the handling robots, and secondly it constitutes a stableinterface enabling positioning to be precise in a fixed frame ofreference associated with the welding robots.

Such tools are generally constituted by a structure for holding abodywork part, which structure comprises members assembled to oneanother together with auxiliary elements secured to the members for thepurposes, for example, of positioning the part in the structure, ofholding the part in the structure, of positioning the structure relativeto another structure, of making a connection with the handling robot, .. . .

These members are formed by beams made from metal bars of lengths thatare determined as a function of the dimensions of the part to be held.With the bars used, it is difficult to have beams that are sufficientlyrigid and lightweight for this purpose.

The beams are usually assembled to one another and to the auxiliaryelements by welding. This means that they are relatively time-consumingand difficult to make, given the deformations caused by welding, andtheir fabrication also requires specialized personnel. Furthermore,repairs and additions of auxiliary elements need to be performed by thespecialized personnel and with very great care so as to avoid spoilingthe shape of the structure. In order to limit deformation, it is commonpractice to make use of beams and of auxiliary elements of considerablethickness, to the detriment of lightness.

It is also possible to make an assembly by bolting. However it isdifficult to position the various beams and auxiliary elements relativeto one another prior to assembling them together. An assembly made inthis way is generally not sufficiently rigid. Furthermore the beams mustbe of relatively great thickness in order to allow fixing screws topenetrate sufficiently, and as a result the beams are relatively heavy.

However, tool weight is an important parameter governing the dimensionsof the robots that are to handle the tools, and having an influence onthe cost of such robots.

OBJECTS OF SUMMARY OF THE INVENTION

According to the invention, a holding structure is provided that is madeup of assembled-together members, with at least one of the members beinga tubular beam provided on the outside with at least onelongitudinally-extending spline.

Thus, the spline can be used as means for stiffening the beam inbending, as an angular positioning marker for an element fixed on thebeam, as means for preventing an element fixed on the beam from movingin rotation, and as a zone for anchoring a screw (the spline forminglocal extra thickness, and thus enabling a screw to be engaged over adepth that is sufficient, while still making it possible to conserveweight that is relatively low). It is thus possible to obtain astructure that is relatively lightweight, robust, and rigid, and that iseasy to implement.

Preferably, the tubular beam has a plurality of splines that areangularly distributed in regular manner around the beam and that presenta section that is substantially circular and symmetrical about at leastone diameter thereof.

This increases the number of options for fixing and orienting beams andelements that are to be fixed thereon.

In a particular embodiment, at least one spline has at least one flankarranged to constitute an angular reference face.

It is then possible to obtain accurate positioning for elements that areto be fixed on the beam.

It is then advantageous for the structure to include at least oneauxiliary element provided with means enabling it to be fixed to thebeam, and for said means to include a face for bearing against thereference face and presser means for pressing the bearing face againstthe reference face, the bearing face preferably being formed by a sidewall of a groove formed in the auxiliary element to receive the spline,and the presser means comprising at least one wedging device for beinginserted between the flank of the spline opposite from the referenceface and the facing side wall of the groove.

This ensures that the auxiliary element is positioned effectively andfirmly relative to the beam.

Also advantageously, the wedging device comprises a chock and at leastone sloping wedge disposed so that the slope of the wedge co-operateswith the corresponding ramp on the chock and so that the chock and thewedge present parallel opposite faces, one for bearing against the flankof the spline opposite from the reference face and the other for bearingagainst the side wall of the facing groove, the wedge being mounted toslide relative to the chock and the wedging device including means foradjusting the position of the wedge relative to the chock.

This method of pressing the bearing face against the reference face isthen particularly simple and effective.

The invention also provides a template for drilling the beam, whichtemplate comprises a body provided with means for releasably fixing iton the beam, and with at least one drilling bushing arranged to extendover a spline of the beam when the template is in position on the beam,said means including a groove which is formed in the body and whichpossesses a first side wall forming a bearing face for pressing againsta first flank of the spline, presser means for pressing the bearing faceagainst the first flank, the presser means comprising a wedging devicereceived between a second flank of the spline and a facing second sidewall of the groove.

This enables holes to be drilled and tapped in a manner that is veryaccurate in each of the splines of the beam so as to make it possiblesubsequently to fix other beams and/or elements thereto.

BRIEF DESCRIPTION OF THE INVENTION

Other characteristics and advantages of the invention will appear onreading the following description of a particular, non-limitingembodiment of the invention.

Reference is made to the accompanying drawings, in which:

FIG. 1 is a fragmentary perspective view of a first structure inaccordance with the invention;

FIG. 2 is a side view of the structure;

FIG. 3 is a section on plane III of FIG. 1;

FIG. 4 is a section on plane IV of FIG. 1;

FIG. 5 is a fragmentary perspective view of a second structure inaccordance with the invention;

FIG. 6 is a fragmentary section view of said structure on plane VI ofFIG. 5;

FIG. 7 is a perspective view of a template for drilling a beam of theFIG. 1 structure; and

FIG. 8 is a section of the template in position on the beam.

DETAILED DESCRIPTION OF THE INVENTION

The invention is described herein in an application to handling abodywork part (not shown), e.g. in an assembly line for motor vehiclebodywork. In particular, the structure shown in FIGS. 1 to 4 is intendedto constitute a lateral tool for manipulating a left-hand body side,said tool being arranged specifically to co-operate with a secondlateral tool for manipulating a right-hand body side and with a reartool for manipulating the rear skirt of the bodywork.

A complete holding structure may comprise a plurality of beams that areassembled to one another by means of auxiliary link elements fixed tothe beams so as to hold them at predetermined angles and positions, andalso fixed on the beams, auxiliary elements for positioning the bodyworkpart within the structure, auxiliary elements for holding the bodyworkpart as positioned in this way, auxiliary elements for fixing thestructure to an arm of a handling robot, auxiliary elements forpositioning the structure in the assembly line or relative to otherstructures, auxiliary elements for making releasable connections to saidother structures, . . . . The holding structure is not shown in full inthe figures, only one or a few beams and a few auxiliary elementsappearing in the drawings so as to illustrate a few possiblecharacteristic configurations.

With reference to FIGS. 1 to 4, the first holding structure of theinvention comprises a beam given overall reference 1 and auxiliaryelements referenced 2, 3, 4, 5, and 6.

The beam 1 is tubular, of circular section, and it is provided withsplines 7 which extend along the outside surface 8 of the beam 1. Inthis case, the splines 7 are fitted onto the outside surface 8 of thebeam 1 by welding, however the splines 7 could be made integrally withthe beam 1, e.g. by extrusion. There are eight splines 7 and they aredisposed at 45° intervals relative to one another. The beam 1 is thussymmetrical.

Each spline 7 has two substantially parallel flanks 9, 10 and a top face11. Some of the splines, referenced 7′ in order to distinguish them fromthe others, include a respective flank 9′ that has been machinedaccurately so as to constitute a reference surface. It is possible forthe beam 1 to have only a single spline 7′.

Tapped holes 12 (visible in FIGS. 3 and 4) and a hole for receiving apin are made radially through the beam 1 from the top surfaces 11 of thesplines 7.

The auxiliary element 2 has one end provided with means 13 (describedbelow) enabling it to be releasably fixed on the beam 1, and an oppositeend provided with a female V-shape 14 for co-operating with a maleV-shape of the rear tool structure to ensure that these two structuresare positioned relative to each other.

Each auxiliary element 5 has one end provided with means 13 forreleasably fixing it to the beam 1, and an opposite end 19 arranged forfixing either positioning members and/or holding members for thebodywork part, or for positioning the structure. By way of example,these members can be clamping means, positioning or indexing fingers orstuds, . . . .

The means 13 comprise a soleplate 22 for bearing against two splines 7disposed at 90° from each other on either side of a spline 7′. Thesoleplate 22 has holes 23 that receive fixing screws 24 with transverseclearance, the screws being engaged in the tapped holes 12 in thesplines 7, and a hole having a pin engaged therein (not shown in thefigures) and received in the hole provided for this purpose in thesplines. A groove 25 is formed in the soleplate 22 to receive the spline7′. The groove 25 is defined laterally by walls 26, 27 that are spacedapart from each other by a distance that is greater than the distancebetween the flanks 9′ and 10′ of the spline 7′. The wall 27 is machinedto form a reference surface for positioning the auxiliary element inco-operation with the flank 9′.

A wedging device given overall reference 28 is received between theflank 10′ and the facing wall 26. The wedging device 28 (more clearlyvisible in FIG. 7, where it is shown mounted on the drilling template)comprises a chock 29 and two wedges 30. The chock 29 has a soleplate 31,and on its opposite side two ramps 32 disposed in such a manner thatthese surfaces form a triangle. Each wedge 30 comprises on the side asoleplate 33, and on the opposite side a slope 34, together with a heel35 at the thick end of the wedge 30. The wedges 30 are disposed so thatthe slopes 34 co-operate with the corresponding ramps 32 and so that thesoleplates 31, 33 bear firstly against the flank 10′ and secondlyagainst the facing wall 26, the heels 35 forming rims that extend overthe ends of the facing chocks 29. A screw (not shown) is mounted to turnin each heel 35 and is engaged in a tapped hole formed in thecorresponding end of the chock 29 so as to enable each wedge 30 to becaused to slide relative to the chock 29, thereby moving the soleplates31, 33 further apart to a greater or lesser extent (the wedges 30 arethus adjustable in position relative to the chock 29). The wedgingdevice thus enables the wall 27 to be pressed firmly against the flank9′. The angular positioning of the auxiliary element is accurate and ismaintained even when large forces are exerted on said element. Becauseof the clearance that exists between the soleplate 22 and the fixingscrews 24, said screws do not oppose positioning of the element. The pinprovides positioning in a direction parallel to the spline.

The auxiliary element 3 is a leg possessing one end fitted with means 13enabling it to be releasably fixed to the beam 1 (said means beingidentical to those described above), and an opposite end 15 that isarranged to bear against the ground or to co-operate with another beam 1via means that are not shown but that are of the same type as the means13.

The auxiliary element 4 is a bracket whose top is provided with means 16enabling it to be releasably fixed to the beam 1, whose first branch hasa free end 17 arranged to bear on the ground or to co-operate withanother beam 1 via means that are not shown but that are of the sametype as the means 13, and a second branch with a free end 18 that isarranged to bear against and be fixed to a corresponding bracket securedto the structure of the righthand lateral tool.

The means 16 comprise a soleplate 36 extending over 180° to bear againstthree splines 7 disposed at 90° intervals to one another, with two ofthese splines 7 lying on either side of the spline 7′. The soleplate 36includes holes 37 that receive fixing screws 24 with transverseclearance, said screws being engaged in the tapped holes 12 in thesplines 7. A groove 38 is formed in the soleplate 36 to receive thespline 7′. The groove 38 is defined laterally by walls 39 and 40 thatare spaced apart from each other by a distance that is greater than thedistance between the flanks 9′ and 10′ of the spline 7′, the wall 40being machined to form a bearing surface pressed against the flank 9′.

A wedging device 28 identical to that described above is housed betweenthe flank 10′ and the facing wall 39.

The auxiliary element 6 has one end provided with means 20 forreleasably fixing it to the beam 1, and an opposite end 21 arranged tobe fixed either to members for positioning and/or holding the bodyworkpart, or to members for positioning the structure.

The means 20 comprise a soleplate 40 for bearing against the top faces11 of two splines 7 that are at 90° from each other, a pin (not shown)that is inserted in the corresponding radial holes of the soleplate andthe spline to serve mainly for positioning the auxiliary elementlongitudinally relative to the beam, and fixing screws 24 passingthrough the soleplate 40 and engaged in the tapped holes 12 of thesplines 7. This element is not required to withstand large forces sothere is no need to provide special means for holding it in positionother than the fixing screws engaged in the tapped holes 12.

The structure made in this way is completely modular, the beams 1 andthe auxiliary elements 2, 3, 4, 5, and 6, being easy to assemble anddisassemble. In addition, the structure is rigid, relatively light inweight, and easy to repair, it being possible to change quickly anycomponents that might become damaged.

It should be observed that when two auxiliary elements have respectivesoleplates that extend over less than 180° (i.e. which overlie no morethan four splines), these two auxiliary elements can be located in thesame plane extending transversely to the beam (see for example FIG. 3).

The holes made in the auxiliary elements 2, 3, 4, 5, or 6 are preferablyall spaced apart by the same distance. This makes it easy to implant anauxiliary element between auxiliary elements that have already beenmounted on the beam, and increases modularity.

With reference to FIGS. 5 and 6, the second holding structure inaccordance with the invention comprises three beams 1 that are entirelyidentical to the beam described above, auxiliary elements given overallreferences 50, 51, and 52 for interconnecting the beams 1 rigidly to oneanother, and auxiliary elements given overall references 53 and 54 forpositioning the structure relative to a stand 55.

The auxiliary elements 50, 51 are arranged to fix two beams 1 to eachother in such a manner that they form an angle of 90°. Each auxiliaryelement 50, 51 comprises two respective soleplates 56 & 57 and 58 & 59for bearing against two splines 7 disposed at 90° relative to each otheron either side of a spline 7′ having a reference flank. The soleplate 56& 57 and 58 & 59, and the associated fixing means are identical to thefixing means 13 and to the soleplate 12 as described above. Thesoleplates 56 & 57 and 58 & 59 extend in directions that form an angleof 90° relative to each other.

The auxiliary element 52 comprises an arm 60 provided at each end withmeans 61 for releasably fixing it to two beams 1 in order to hold themparallel to each other. The means 61 are identical to the fixing means13.

The auxiliary elements 53 are identical to the auxiliary element 6 andeach of them is fixed to one of the parallel beams 1 in the same manneras the auxiliary element 6. Each auxiliary element 53 has a free endprovided with a housing 62 for receiving a pilot 63 secured to the stand55. The auxiliary elements 52 and 53 extend substantially in the sameplane extending transversely to the beam 1.

The auxiliary element 54 is identical to the auxiliary element 6 and isfixed to one of the beams 1 in the same way. The auxiliary element 64has a free end provided with a fork 64 for sliding along a rail 65secured to the stand 55.

The tapped holes 12 and the smooth hole for the pin are made in thesplines 7 by means of a drilling template shown in FIGS. 7 and 8, andgiven overall reference 100 in these figures.

The template 100 comprises a body 101 provided with means 102 enablingit to be releasably fixed on the beam 1, and drilling bushings 103disposed to extend over a spline for drilling when the template is inposition on the beam 1.

The means 102 comprise a soleplate 104 for bearing against the top faces11 of two splines 7 for drilling that are disposed at 90° from eachother on either side of another spline 7 used or positioning thetemplate 100. A groove 105 is formed in the soleplate 104 to receivesaid spline 7. The groove 105 is defined laterally by walls 106 and 107that are spaced apart by a distance that is greater than the distancebetween the flanks 9 and 10 of the spline 7. The wall 107 is machined toform a reference surface for angularly positioning the auxiliary element2 in co-operation with the flank 9 of the spline 7 used for positioning.A wedging device 28 identical to those described above is receivedbetween the flank 10 and the facing wall 106.

The means 102 further comprise clamping means 108 of the “grasshopper”type for bearing against the top faces 11 of two splines 7 opposite fromthe splines 7 that are to be drilled so as to press the soleplate 104against the top faces 11 of the two splines 7 that are to be drilled.Other clamping means could be used.

The template 100 is put into place on a spline 7 and is positioned alongit by using positioning means. The positioning means may be constitutedmerely by measuring a distance from a predetermined reference point onthe beam or by using a longitudinal positioning template.

When the template 100 is in position, the drilling bushings 103 extendover the splines 7 for drilling.

The template 100 may be arranged to enable more than two splines 7 to bedrilled, and may optionally be made in two parts so as to enable all ofthe splines to be drilled.

It should be observed that the retaining spline for positioning thetemplate 100 on the beam 1 is preferably a spline 7′ so as to make useof the flank 9′ thereof in order to ensure accurate positioning of thetemplate. Drilling bushings may also be provided for drilling thespline(s) used for positioning.

Naturally, the invention is not limited to the embodiments describedabove, but on the contrary it covers any variant using equivalent meansto reproduce the essential characteristics specified above.

In particular, the number of splines and the way in which they arearranged can be different from those shown, the beam 1 need not besymmetrical, or it may be symmetrical about only one of its diameters.

In addition, means other than the described wedging device could be usedfor pressing the reference wall of the groove against the referenceflank 9′ of the spline 7′, for example a clamping device using aneccentric.

Furthermore, the beam 1 may have a plurality of splines 7′ each with arespective flank 9′ arranged to form a positioning reference.

Clamping means, e.g. analogous to those of the template 100, may also beused for fixing auxiliary elements to the beams. The auxiliary elementscould also bear against one spline only.

1. A structure for holding a bodywork part, the structure being made upof assembled-together members, wherein at least one of the members is atubular beam (1) provided on the outside with at least one spline (7)extending longitudinally and including at least one reference flank (9′)arranged to constitute a positioning reference for at least oneauxiliary element (2, 3, 4, 5) having a soleplate (22, 36) provided withmeans (13, 16, 24) for fixing it to the beam, said means including abearing face (27, 40) for pressing against the reference flank (9′) andpresser means (28), bearing on another flank (10′) of the spline (7′)that is opposite from the reference flank (9′), for pressing the bearingface against the reference flank, wherein the bearing face is formed bya side wall (27, 40) of a groove (25, 38) formed in the auxiliaryelement (2, 3, 4, 5) for receiving the spline, and wherein the pressermeans comprise at least one wedging device (28) for inserting betweenthe another flank (10′) of the spline (7′) that is opposite from thereference flank (9′) and the facing side wall (26, 39) of the groove(27, 40).
 2. A structure according to claim 1, wherein the beam (1) hasa plurality of splines (7) that are angularly distributed regularlyaround the beam.
 3. A structure according to claim 2, wherein the beam(1) presents a section that is substantially circular and symmetricalabout at least one diametral axis thereof.
 4. A structure according toclaim 1, wherein the wedging device (28) comprises a chock (29) and atleast one sloping wedge (30) disposed so that the slope (34) of thewedge co-operates with a corresponding ramp (32) of the chock, andwherein the chock and the wedge present two parallel opposite faces (31,33) for bearing one against the another flank (10′) of the spline (7′)opposite from the reference flank (9′) and the other for bearing againstthe facing side wall (26, 39) of the groove (25, 38), the wedge beingmounted to slide relative to the chock and the wedging device includingmeans for adjusting the position of the wedge relative to the chock. 5.A structure according to claim 1, wherein the fixing means include atleast one screw (24) for engaging in a tapped hole (12) formed in thespline (7) in a radial direction of the beam.
 6. A structure accordingto claim 1, wherein the beam (1) has a plurality of splines (7), and thesoleplate (22, 36, 40) of the auxiliary element bears against at leasttwo splines.
 7. A structure according to claim 6, wherein the soleplate(22, 36, 40) extends over an angle of no more than 180°.
 8. A structureaccording to claim 1, wherein the auxiliary element is arranged toconnect two beams (1) together at a predetermined angle.
 9. A drillingtemplate (100) for a beam (1) provided on the outside with at least onespline (7) extending longitudinally and including at least one referenceflank (9′) arranged to constitute a positioning reference for at leastone auxiliary element (2, 3, 4, 5) having a soleplate (22, 36) providedwith means (13, 16, 24) for fixing it to the beam, said means includinga bearing face (27, 40) for pressing against the reference flank (9′)and presser means (28) bearing on another flank (10′) of the spline (7′)that is opposite from the reference flank (9′) for pressing the bearingface against the reference flank, the template comprising a body (101)provided with means (100, 104) for releasably fixing it on the beam, andwith at least one drilling bushing (103) arranged to extend over aspline (7) of the beam (1) when the template is in position on the beam,and wherein said means include a groove (105) which is formed in thebody and which possesses a first side wall (107) forming a bearing facefor pressing against a reference flank (9) of the spline (7), pressermeans for pressing the bearing face against the reference flank, thepresser means comprising a wedging device received between a secondflank (10) of the spline and a facing second side wall (106) of thegroove.
 10. A template according to claim 9, wherein the wedging devicecomprises a chock (29) and at least one sloped wedge (30) disposed sothat the slope (34) of the wedge co-operates with a corresponding ramp(32) of the chock, and so that the chock and the wedge present twoparallel opposite faces (31, 33) for bearing one against the secondflank (10) of the spline (7) and the other against the second side wall(106) of the groove (105), the wedge being mounted to slide relative tothe chock, and the wedging member including means for adjusting theposition of the wedge relative to the chock.
 11. A structure for holdinga bodywork part, the structure being made up of assembled-togethermembers, wherein at least one of the members is a tubular beam (1)provided on the outside with at least one spline (7) extendinglongitudinally and including at least a first flank (9′) arranged toconstitute a positioning reference flank (9′) for at least one auxiliaryelement (2, 3, 4, 5) having a soleplate (22, 36) provided with means(13, 16, 24) for fixing it to the beam, said means including a bearingface (27, 40) for pressing against the reference flank (9′) and pressermeans (28) for pressing the bearing face against the reference flank(9′), wherein the bearing face is formed by a side wall (27, 40) of agroove (25, 38) formed in the auxiliary element (2, 3, 4, 5) forreceiving the spline, and wherein the presser means comprise at leastone wedging device (28) for inserting between a second flank (10′) ofthe spline (7′) that is opposite from the reference flank (9′) and thefacing side wall (26, 39) of the groove (27, 40).
 12. A structureaccording to claim 11, wherein the beam (1) has a plurality of splines(7) that are angularly distributed regularly around the beam.
 13. Astructure according to claim 11, wherein the beam (1) presents a sectionthat is substantially circular and symmetrical about at least onediametral axis thereof.
 14. A structure according to claim 11, whereinthe wedging device (28) comprises a chock (29) and at least one slopingwedge (30) disposed so that the slope (34) of the wedge co-operates witha corresponding ramp (32) of the chock, and wherein the chock and thewedge present two parallel opposite faces (31, 33) for bearing oneagainst the second flank (10′) of the spline (7′) opposite from thereference flank (9′) and the other for bearing against the facing sidewall (26, 39) of the groove (25, 38), the wedge being mounted to sliderelative to the chock and the wedging device including means foradjusting the position of the wedge relative to the chock.
 15. Astructure according to claim 11, wherein the fixing means include atleast one screw (24) for engaging in a tapped hole (12) formed in thespline (7) in a radial direction of the beam.
 16. A structure accordingto claim 15, wherein the soleplate (22, 36, 40) extends over an angle ofno more than 180°.
 17. A structure according to claim 11, wherein thebeam (1) has a plurality of splines (7), and the soleplate (22, 36, 40)of the auxiliary element bears against at least two splines.
 18. Astructure for holding a bodywork part, the structure being made up ofassembled together members, wherein at least one of the members is atubular beam (1) provided on the outside with at least one spline (7)extending longitudinally and including at least a first flank (9′)arranged to constitute a positioning reference flank (9′) for at leastone auxiliary element (2, 3, 4, 5) having a soleplate (22, 36) providedwith means (13, 16, 24) for fixing it to the beam, said means includinga bearing face (27, 40) for pressing against the reference flank (9′)and presser means (28) for pressing the bearing face against thereference flank (9′), wherein the auxiliary element is arranged toconnect two beams (1) together at a predetermined angle.